The present invention relates to an apparatus for automatically taking a reading of the shape and/or the profile of the inner contour of a rim of a frame of glasses.
To construct pairs of corrective glasses by an automated procedure it must be possible to effect precisely and automatically the grinding of the lenses of these glasses with a grinding machine controlled with data, which include in particular the geometrical parameters providing an exact definition of the shape and profile of the outer contour of the lenses. These parameters depend, on one hand, on the physiological parameters of the user of the pair of glasses, such as in particular the distance between the pupils of the eyes and the position of the eye with respect to the lens and, on the other hand, on the shape and/or the profile of the inner contour of the frame rim of the glasses receiving the lens.
Many methods and devices have been proposed which permit automatically taking a reading of the last-mentioned data. However, it has been found that all the devices employed at the present time do not permit obtaining a sufficient precision of the reading or a sufficiently fine definition, in particular owing to the use of mechanical followers which are only rarely perfectly adapted to the profile of the inner contour of the rim explored by the followers, as well as a complete angular scanning of this inner contour.